JavaScript OOP programming-three ways to implement inheritance

JavaScript OOP Programming-three forms of implementing inheritance [1]

(1) The way of simulating the class, we all know that JS is a prototype inheritance mechanism, there is no class and instance separation of this way

Let's say we have two of classes.

function Animal () {

THIS.name = "Animal";

This.eat = function () {

Consle.log ("eating");

}

}

function Cat () {

This.say = function () {

Console.log ("Miao miao!!");

}

}

If we want cat to have the animal name attribute and the Eat method, you only need to

Cat.prototype = new Animal ();

But this is not a good practice, think about, if there is a duck class, do you want to new a animal to inherit, so continue?

The right thing to do is to put the generic content into the prototype, all the heirs, simply point their prototype to a generic prototype to implement the inheritance.

As follows

Animal.prototype = {

Name: "Animal",

Eat:function () {

Console.log ("eating");

}

}

Cat.prototype = Animal.prototype;

ES5 provides us with a generic inheritance function that creates an object from a specified prototype

Object.create unfortunately not all browsers support, manually change

var inherit = Object.create | | function (proto) {

function F () {};

F.prototype = Proto;

return new F

}

The above example can be written as

Cat.prototype = Inherit (Animal.prototype);

——————————

In doing so, there will be cat.prototype = F case, we need to go to the right, we should write a package, specifically to implement the inheritance

var extend = function (child,parent) {

Child.prototype = Inherit (Parent.prototype);

Child.prototype.constructor = child;

}

JavaScript OOP Programming-three forms of implementing inheritance